The purpose of Core E is to provide high quality results for total and allergen-specific IgE to Projects 2 and 4. The value of centralizing this testing is to reduce variation in the results and to gain purchasing efficiency by combining ordering for all reagents to a single laboratory. The Pediatric Allergy-Immunology Laboratory at Georgia Health Sciences University is CLlA-certified for patient care assays and participates in the quality , assurance program of the College of American Pathologists (CAP) for IgE testing. This laboratory has performed all of the IgE tests for the WHEALS study to date. The coefficients of variation for repeat assays are consistently in the range of 6% or less. Data from all assays is transmitted directly electronically from the analytic instruments to the study coordinators in Detroit for entry into the study database. This eliminates the risks of data corruption from transcription and transmission of data. Dr. Dennis Ownby, who will oversee the performance of the IgE assays, is highly knowledgeable in the area of IgE testing and he will assure the quality of the results reported for analysis in the proposed studies. A system of careful sample tracking and identification based on bar coding all samples has been developed which minimizes the risks of sample loss during shipping or of not matching samples and the results from testing the sample. As in the past, 1% of all samples will be re-assayed weeks to months later to assure quality control and to assure that all samples are correctly identified.